Musnad Ahmad 5:246

Abdullah narrated to us, Muhammad ibn Ja’far al-Warkani narrated to us, in the year two hundred and twenty-seven, Abu ‘Aqil Yahya ibn al-Mutawakkil narrated to us, and Muhammad ibn Sulayman Luwayn narrated to us, in the year two hundred and forty, Abu ‘Aqil Yahya ibn al-Mutawakkil narrated to us, from Kathir al-Nawa, from Ibrahim ibn Hasan ibn Hasan ibn ‘Ali ibn Abi Talib, from his father, from his grandfather, who said: ‘Ali ibn Abi Talib said: The Messenger of Allah, peace and blessings of Allah be upon him, said: "There will appear at the end of time a people who will be called the Rafidah; they will reject Islam."